1. NAME AND TITLE

FORSEN: A Multigroup Processing Code for Use with Sensitivity Profiles to Assess the Effect of Cross Section Changes.

2. CONTRIBUTORS

Brookhaven National Laboratory, Upton, New York.

Southern Company Services, Birmingham, Alabama.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; IBM 360/370.

4. NATURE OF PROBLEM SOLVED

The FORSEN code computes spectrum-averaged group cross sections for two input cross-section files and provides systematic information for use with sensitivity profiles to estimate the effect due to changes between the two sets (e.g., ENDF/B-IV vs. ENDF/B-V evaluations).

5. METHOD OF SOLUTION

The input to the code is provided by RESND¹-LINEAR² -SIGMA1³ output in ENDF format. Two input files can be processed simultaneously. The output is the spectrum-averaged cross sections and their corresponding percent changes between the two input data sets over a specified number of groups (up to 200). The percent change in group-averaged cross sections between two data sets, e.g., ENDF/B-IV and V, for a particular material is used in the SENTINEL⁴ code to evaluate the sensitivity of integral parameters of selected fast and thermal benchmarks to the change in certain basic nuclear data (e.g., ENDF/B-IV and V). In the present version of the code only four reaction cross sections, namely, the total (MT=1), elastic scattering (MT=2), capture (MT=102), and fission (MT=18), are processed.

6. RESTRICTIONS OR LIMITATIONS

The number of input cross-section points is 32,000. The number of groups that can be calculated is 200. The number of energy weight pairs for the weighting spectrum is limited to 1300. Any of these limits can be changed by modifying DIMENSION statements.

7. TYPICAL RUNNING TIME

The sample problem, a 3-group comparison of ENDF/B-IV and -V U-235 data, took only 11.81 seconds of computer time on the IBM 370/3033.

8. COMPUTER HARDWARE REQUIREMENTS

On the IBM 370/3033, the sample problem required 236 K in the GO step.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran IV compiler is required.

10. REFERENCES

a. Included in documentation:

A. Alapour, "Informal Notes" (May 1979).

b. Background information:

O. Ozer, "RESEND: A Program to Preprocess ENDF/B, Materials with Resonance Files into a Pointwise Form," BNL-17134 (1972).

D. E. Cullen, "Program LINEAR (Version 79-1): Linearize Data in the Evaluated Nuclear Data File/Version B (ENDF/B) Format," Volume 17, Part A, Rev. 2, UCRL-50400 (October 1979).

D. E. Cullen, "Program SIGMA1 (Version 79-1): Doppler Broaden Evaluated Cross Sections in the Evaluated Nuclear Data File/Version B (ENDF/B) Format," Volume 17, Part B, Rev. 2, UCRL-50400 (October 1979).

J. H., Marable, J. D. Drischler, and C. R. Weisbin, "SENDIN and SENTINEL: Two Computer Codes to Assess the Effects of Nuclear Data Changes," ORNL/TM-5946 (July 1977).

11. CONTENTS OF CODE PACKAGE

Included are a brief referenced document containing input instructions and one (1.2MB) DOS diskette which contains the source program and sample problem input and output.

12. DATE OF ABSTRACT

January 1982; August 1984.